Telephone system



Peli 15, 1944. D. L CLAY 2,341,693

TELEPHONE SYSTEM AFVID LA NGSFORD CLAY Afro/PNE? Feb. 15,v 1944. D CLAY y 2,341,693

TELEPHONE SYSTEM Filed sept. 17 1941 y:5 sheets-sheet 2 ngz.

Amun" @if y Y, u v g' Humm-yf@ )NMEA/rok DAVID LANGSFORD cLAY` Arm/vn Feb.'15, 1944. D. 1 LAY TELEPHONE SYSTEM Filed Sept. 17, 1941 3 Sheets-Sheet 5 MWF/V703 DAVID LANGSFORD CLAY y I: Z

Patented Feb. 15, 1944 TELEPHONE SYSTEM David Langsford Clay, London, England, assignor to Siemens Brothers & Co. Limited, London, England, a. British company Application September 17, 1941,.Serial No. 411,121 In Great Britain September 30, 1940 12 Claims. ('Cl. 179-18) Thepresent invention relates to telephone systems and is especially applicable to private automatic and private automatic branch exchange systems. The chief object of the invention is "to provide improved means for disposing of calls to privilegedparties who may vbe absent from their instruments or who do not wish to be disturbed.r

According to the present invention apparatus is associated with a privileged subsoribers` line at the exchange and is adapted to be inuenced by an operation on thel part of the subscriber whereby calls directed by the exchange switching apparatus to the privileged subscribers connection in the nal selector multiple maybe extended as desired to avcircuit from which-an answer or distinctive signal. or other information-can be given to the caller. VFor extending the call the apparatus conveniently includes a selecting switch adapted to be set in response to impulses transmitted by the privileged subscriber or by a marking applied by relays responsive to key operation by the privileged subscriber,A the selecting switch having wipers connectable tol contacts in the bank of the iinal selector appropriate to the privileged subscribers number, outlets from the selecting switch being connected to the circuits to which a call maybe extended. The apparatus maybe so .arranged that when the privileged subscribers line is called, whether the call is to be extended ornot, a tone or recorded message is given to the caller to indicate that'he is calling a privileged line and completion of the call may be delayed pending further action by the caller or the arrangement may be such that only calls to beextended are so dealt with or again the privileged subscriber may decide at the time of setting the apparatus whether calls are to be directly connected or held in suspense.

' `The arrangements provide that while the apparatus is set for the extension of a call to another circuit the privileged partys line is available for use yfor outgoing calls.

The apparatus the subject of the invention can conveniently be connected to an existing system at the intermediate distributing frame or if such aframe is not provided, the existing wiring may be suitably out and connected to terminals to which the apparatus may be connected thus avoiding disturbance of the multiple wiring. Access to the apparatus for the purpose of influencing it may be had by dialling a number appro- 'priate to its connection in the banks of the nal selector or a special connection may be provided over a controlling key and the impulsing or marking for the selective action may then be performed.

A speciiic embodiment of the invention'will new be described by way of-example--witli reference to the accompanying drawings comprising Figs. 1 3. VIn the drawings Fig. 1 shows diagrammatically .the connections at a private automatic exchange (P.A. X) of an ordinary subscribers line and the' line of a privileged subscriber with which the automatic switching apparatus pro--l videdfor the purpose of the invention is associated. VFigs. 2 and 3 show the circuit arrangements of the automatic switching apparatus.

Referring first to Fig. 1, it will be seen that the lines of all subscribers terminate on an inter-v mediate distributing frame IDF where they are jumpered as required to the line circuits and the final selector multiple.V The line of an ordinary subscriber designated OS is connected over the frame IDF to a line circuit OLC and over wire os to contacts in the final selector Amultiple designated by the number of the said ordinary subscriber. The line of a privileged subscriber designated PS is connected over `the frame IDF to a line circuit PLC and also to the normaland -rst contacts of a selecting switch designated RR in the automatic switching apparatus. The contactinithe nal selector multiple designated by the number of the privileged subscriber is connected by wire ps over the IDF to the automatic switching apparatus designated by the reference MS from which it is extended bythe switch RR in a manner` determined by the setting of this switch. For the setting of the switch RR the automatic switching apparatus MS is connected over the IDF by a wire ms to a Contactin the iinalselector multiple to which the final selector may beset for the purpose of exercising control of the apparatus which includes the swtchrRR. The outlets from the switch RR are connected to lines .of ordinary subscribers over the IDF, one particular connection being shown from contacts 2 and 3 of the switch to line OS. lThe contacts of the switch are connected in pairs for a, reason which will be clear from the description about to be given of Figs. 2 and 3. The last contacts of the switch are connected to a tone circuit. o The .connecting arrangements in the exchange are shown simply as consisting of a line nder LF and nal selector FS, it being understood that one or'more selecting switches can be Vincluded in the connection between'the line-lnder and iinal se:- lector and that arrangements for selecting v:and controlling a line Viinder would-.be provided in known manner.

f If an. intermediate distributing frameisnot provided it'will be `necessary toV allot two'posi+ tions in vthe nal selector multiple .for the priv-` iliged subscribers line, one suchpositionibeing connected to the automatic switching apparatus the other being left disconnected. The linexcr.- cuitfcorresponding to .the'iormer position will be disconnected as will also ithe 'line Icircuit .corresponding to the position in the multiple .com-

nected to the automatic switching apparatus for its setting.

Reference will now be had to Figs. 2 and 3 of the drawings. On the left of Fig. 2 are shown diagrammatically the speaking and test wire wipers and their contact banks of nal selectors,

FS. The outlets from the banks of the final j selectors are multiplied in the usual manner and in the upper of the two selectors shown the outlet for the control of the automatic switchingapparatus MS is shown while in the lower of the two selectors the outlet shown is that corresponding to a privileged subscribers line. The apparatus MS comprises an l1-contact single motion reverse drive stepping switch RR having 7 wipers and contact banks and driven by magnet RM. The .rst 10 outlets from the switch in the banks of wipers RRS, RRS and .RR'I are connected in pairs, contacts Il and l being connected to the privileged subscribers own line, contacts 2 and 3 and so on to contacts 8 and 9 being connected to the lines of other subscribers to which .an .in. coming call can be extended by the apparatus. The last contacts, i. e., contacts Ill, are connected to a tone circuit. The .off-normal contacts .in the bank of wiper RRI are commoned; similarly, the off-normal contacts in the bank of wiper RRZ are commoned. I'he setting of the switch RR is controlled by relays A, B and C and relays P .and Q determine the contact of a .pair over which a call is to be extended.. These relaysare operated on alternate impulses and by their con- -dition at the end Yof an impulse. train determine whether the call shall be extended directly or only after some further action `has been performed lby the cal-ler, and in the latter case a Aguard the line at this time. If the switch RR is in the normal position, relay A in the apparatus MS -operates over a preceding loop and at. contact a2 closes a `circuit over Wiper RRZ on contact U forrelease relay B. Relay B operates and at contact bl opens the homing circuit for switch RR, at contact b2 prepares a holding circuit for itself, at contact b3 prepares a circuit for relay C and Vat Contact b4 connects dialling tone over wire DT, contact 0 and wiper RRA to a third winding of relay A. This tone is transmitted to the caller by induction inthe line windings of relay A.

When the first impulse of the setting train is dialled, relay A falls *back during the break" period of the impulse and at contact al operates relay C. On the subsequent reoperation of relay A a circuit is closed over contacts al and cI for magnet RM which becomes energised. vAt the same time a circuit is closed 'over contacts a2 and c2 'for the right-hand winding .of relay l?.l .Relay P operates and at contact pl prepares an yenergising circuit for itsy left-hand winding and at contact p2 prepares a holding circuit for itself and an operating circuit `for relay Q. If fur-ther c impulses follow, relays B vand C hold during such tone is reverted tothe caller to inform him that 1 further action is required. In thisway it is possible for theV caller to abandon the .call if .the matter is not suiciently urgent to warrant disturbing the privileged subscriber. The switching through of the connection is-.carried out by the relays shown in the lower part of the figures, I-I being a test relay and TR. a ringtripping relay. Relay AA responds to .a further impulse. train which may comprise any number of impulses fdialled in response. to a tone revertedover wire RT. BB and CC-are slow .releasingreleaseand dialling relays respectively and VE is a slowreleasing relaywhich measures :ofi a fleetingI test period'. ON- is a relay the function of which corresponds to the more usual oft-normalacontacts of the selecting switch RR.

In the normal positionof `the switch RRJca-lls to the privileged subscriber are extended Yby the final selector over unoperated contacts q2., q3. and 14 of relay Ql and wipers RR5, RRS and RRI in theirnormal or 0. contact position to the .privileged subscribers line, the called line` being marked busy by earth applied. in the i-lnal selector over the test wiper thereof and. wiper RRI..

Ify the privileged subscriber does not wish rto lbeA disturbed except on an urgent matter, or if he leaves his instrumenty and goes to the position of another subscriber to whose line an incoming call can be extended by the. apparatus .MS or if he. leaves his instrument and goes to a position to which the. apparatus. MS cannotV extend a call, for example from the exchange sys.- tem, he sets the apparatus MS accordingly. To -do this he dials the number allocated to the appa.- ratus and thenv by means of a further impulse train he sets it to thedesired position. rllhis can be done from .any telephone on the?. A. .X sysimpulsing. At the second release of relay Amaz-v net RM .is de-energised and, steps the lwipers to contacts l. Wiper RRZ is now included .in `the holding circuit for relay B, contacts lI to l0 in the bank associated with wiper RR2 being commoned. A short circuit is removed from winding (I) of relay Q .atycontact a2 and this relay opervates by means of its` winding. (I) in series with the right-hand winding 'of relay P and wiper RRB. Contact ql disconnects the .right-hand winding of .relay P from the circuit .over contact a2 and connects thejleft. hand, winding of that relay in its place.l When relay Are-operates. the left hand winding of relay P is energised and as this winding is `arranged to oppose the, right-hand winding, the rrelay .is released. Winding (Il). of relay Q is energised in parallel with vrelay P and` relay Q remains; held. 'lhus after each odd. impulse, relay P-remains operated and after each even impulse .relay Q remains operated: until the nextY impulse break. occursfor relay C releases consequent. on the continued energisaticn of relay A.

When the switch has. been :set .to the desired position by the transmission ofthe appropriate impulse train, the privileged subscriber replaces his receiver and takesno Afurther action until` he desires to alter the setting; consequently relay A Vreleases followed by` relaysY B-r and C; If. an veven number of. impulses has been transmitted' for the setting of the switch. the; opening. of contact c2 following the continued operation of; relay A after thetransmission of the last., iin-pulse releases re.- lay Q and; similarly4 if an odd number of impulses .have been transmitted theI removal of the shortcircuit about winding (I) of; relay Q is similarly performed; Relay N releases andv removes the engaged marking. from the privileged subscribers line. Al call for the privileged subscriber is now extendedv overone of the contacts 0/ to 9V or the connection is routed to a tone circuit over contacts Ill o f the switch RR. A

'If-o; cha-nee the. Settinsf switch-RR 1mm-,One

onf-normal position to. another position the Drivileged subscriber dials the number allocated to the apparatus and relay Aoperates. Relays B and C being unoperated and the switch being away from its normal contacts, a circuit is closed over contacts a, cl, contacts rm operated by magnet RM, wiper RRI and contact bl for magnetRM and the magnet operates by4 self-interruption to home the switch. In the home position relay B operates and connects up dialling tone and the subscriber can thenproceed with the settingof the switch if such a f urther setting is desired.

If the switch has been .set to onevof, the even contacts 24, 6,8, I0, an incoming call is ex tended directly to the line of the subscriber connected to the particular contacts or to the tone circuitwhile if the switch has been set to one of y are as follows. Relay Q has remained operated after the setting of the switch and battery potential for the final test relay is applied over contact qll and relay AA is connected to the speaking wires over contacts q2 and 13. When'the apparatus is seized, relay AA operates over apreceding loop and at contact aal operates relay BB. Contact bbl connects tone over wire RT and contact oni to a third winding on relay AA and the tone is transmitted to the caller by induction in the other windings of relafs7 AA. On hearing the tone the caller dials another impulse train which may comprise a single impulse or any number of impulses. When relay AA releasesacircuit is closed over contacts aaZ, bbl-l and :13 for relay CC and this relay operates. Contact ccl prepares a circuit for' relay Eg'contact co2 closes a holding circuit forrelay CC and contact co3 disconnects the testing circuit of relay H. When relay AA re-operates, contact cd2 completes the prepared circuit for relay E and this latter relay operates. Contact el operates relay ON which holds over contacts l011.2 and hb2, Contact e2 connects relay I-I to the test wiper RR'I, contact e3 disconnects the busy and ringing signal circuits and contact e4 disconnects winding (I) of relay TR. Contact oni disconnects tone wire RT and prepares for the'transmissionA of ringing or busy signal `and contact cm3 opens the operating circuit for relay CC. Any further impulses in the train produce no eiective circuit changes. When relay AA remains steadily operated after the last impulse of the additionaltrain has been transmitted, relay CC releases and at contact co3 closes the testing 'circuit for relay H. If the line is free, relay H operates over its right-hand winding and locks up over its left-hand winding and contacts hl and hb2. Contacts h2 and h3 connect the line wires to wipers RRE and RRG, contact h4 earths the test wiper RRT to mark the line engaged and contact h5 connects up wire RS over which ringing signal is transmitted. Shortly after the operation of relay H, relay E releases consequent on the opening of contact ccl and Contact e2 disconnects the right-hand winding of relay H, contact e3 connects wire RS over contacts tr4, h5, onl and bol to the third (winding on relay AA and contact e4 connects relay TR in the ringing circuit. rl'he bell of the subscriber connected up over the wipers of switch RR is rung inthe usual manner and the caller receives a ringing signal over wire RS. lWhen the called party replies, relay TR operates, closes a locking circuit for itself over its winding (II) and contacts trl and hb2, switches the line through at contacts tr2 and tr?) and disconnects the ringing signal at tional condition.

When the caller clears at the ,end of the con-- If the switch has been set to contacts l, relay H operates as for a free line and a circuit i'or. relay TR is completed immediately relay E re leases and a number unobtainable or otherdis-` tinctive tone is reverted from a circuit connected to contacts l0. If it be desired that all over contacts other than the normal are tobe held in suspense, relays P and Q can be dis-.

pensed with and anoff-normal relay may be connected between a back contact of contact d2 vand wiper RR3, the normal contact in the`bank of` this lwiper being unconnected and the ofi normal contacts connected to battery. Contactsoi .this relay would be substituted for contacts 2, 3 and 4 vof relay Q and only one position per circuit to which callsmay be extended would be required in the banks of wipers RRE, RRS fand RRI. Obviously by omitting relays P and Q Y or the offnormal relay referred to and connecting the contacts allocated to the privileged subscriber in the l oar 1kl ofthe nal selector directly `to relay AA- and contacts t2 vandrtr and connecting the testwre Contact over the back oi contact nl.

directly to battery all calls can be arranged tobe held in suspense. i l

If the privileged subscriber is conveniently situated with respect to the exchange and if it is.

not desired to effect a setting of the apparatus MS Ifrom any position other than the privileged subscribers position, setting vmay be effected bysa marking applied to the switch by relays operated by means of a set of keys at the privileged subscribers location. Such means are well known in the art and consequently a particular description. of such means has not been thought necessary.,

Although the switch RR has been described and illustrated herein as an 11point single motion switch, a largerrswitch or a two motion switch maybe employed, kthe means yfor setting such a switch taking any well-known form. i A,

VIt will be appreciated that the arrangements shown can be added to an exchange without disturbing the existing circuits, all Athat is necess ary= being to4 connect thev apparatus as requiredto terminals on the intermediate distributing frame thatwhile the switch RR is in an oii-normal position the privileged subscriber is quite free to,

make outgoing calls in the ordinary manner.

What I claim as new and desire to secure by Letters Patent is: v

1. In a telephone or like system, a calling subscribers line, a called subscribers line, switching equipment normally responsive to certain predetermined operations performed by the calling subscriber to seize said called line, if same contact trl. The,circuit is now in the conversa' aus to be extended.

is: free, preparatory to rthe7 completion ofa call thereto, means for at times preventing said7 equipment from seizing. said calledl line even though same is free, means for signalling. the calling subscriber at suchv times, and melans thereafter operated responsive to an additional operation performed by the calling subscriber for seizing said called line.

2 In a--telephoneori'like system', al callingfsubscriber's line', an idle called subscribers line, switching equipment: normally responsive tocertain predetermined operations periormedf'by the callingsubscriber' to seize said idle called line, and means operated at times for' causing said equipment to seize said idle called line respon-v sive only to an additional operation performedy by said calling subscriber after said" predetermined operations have been performed.

3. In a telephone orlike system, a calling sublscribers line, an idle calledV subscribers line, switching equipment normally responsive tocertain predetermined operations-performed by the calling subscriber to seize said idle called line, and means at times pre-set over one ofsaid lines prior to performance' of said-predetermined operations for' causing said equipment to seize saidv idle called line responsive only to anaddi-A tional operation, performedv by said calling subscriber after said predetermined operations` have been performed.

4'. In a telephone or likesystem, an automatic switch having a Contact bank; a plurality of lines each normally appearing in but a single'position in the bank of said switch, and means operated variably to cause any desired oneuk of said lines to appear in a plurality of positionsl in the bank of said switch, whereby a subsequent operation of said switch to any of said plurality of positions will select said one line.

5. In a system as claimed in claim 4, meansin said switch for seizing said'one line substantially' without delay if it is selected by 'operation ofsaid-` switch to a particular one o'isaid plurality of positions at a time when said one line is idle,y and means for delaying the seizure of saidline if it'is' selected by operation ofy said switch to a differentv one of said plurality of positions at a time when' said one line is idle.

6. In a telephoneor like system, an automaticV switch having wipers and a bank ofcontacts ac-j cessible to said wipers, means for'moving' said` wipers to engagean'y set of contacts in said bank, at least three lines each normally connected-to but a single set of contacts-in said bank, and' means operated selectively to c'auseany' desired one of said lines to be connected to atleast one' additional set of contacts in said bank, whereby said one line thereafter may beselected by opera' tion of said wipers to any ofa `pluralit'y'of dif'- ferent sets of contacts in the bank of said switch.`

7. In a telephone or like system, an automatic switch having wipers occupyingv anormal position and a bank of contacts accessibleY to said wipers,- a plurality of lines each permanently connected to a different set of`V contacts in said bank, a special set of contactsY` in said bank, meanslf'or moving said wipersf'oii normal-.to select a-nysetfofy contacts in said bank, selector means operated'l variably over said wipers when same occupya particular oi-normal position to connect any desired one of said lines to said special contact set, means .for lthen restoring said Aswitch to noraangetaniallwitliout disconnecting said one line from said speci-al contact set; whereby said one vline thereafter may be' selected by the movement of said wipers, under control of said rst means, either to saidspecial contact set'or to the contact set to which said one line is' permanently connected. y I

48-. In atelephone or like system, a ii-'rst switch, a second switch` accessible tosaid' rst switch, a plurality oi"Y subscribers lines each connected in multiple to theA contact banks' of both said switches, means for operating either of Vsaid switches Vto connect directly with any desiredone ofsaid lines over the contact bank of that-switch, said means effective at times to cause said rst switch to connect with said second switch while said second switch remains' connected to some one ofy said lines to which it was previously operated, thereby to connect with said lastementione'd line over said two switches in series.

9-. In a telephone or like system, a rst switch, a second switch accessible to said first switch, a plurality' of subscribers lines' each connected in multiple to the contact banks of both said switches, and means for extending a call to any desired one'of said lines' veither by seizing said rst switch and operating it to select said desired line in its own contact bank or by operating saidy second switch to select said desired line and then seizing said rstswitch and operating it to 'select said second switch.

' 10. In a system as claimed in claim 9, means response to" said signal for seizing said desired line.

l1'. In a telephone or like system, a. hrst switch; a second switch accessible to said first switch,

a plurality of subscribers lines each connectedv in multiple to the contact banks of lboth said switches, means for seizing saidV rst switch, operating it to seize said second switch, and then operating said second switch over said nrst switch to connect withv any desired one of s'aid lines', means forv thereafter releasing said iirst switch without releasing` said second switch, and' means for subsequently seizing said one line either by operating said nrst switch to connect directly with said one line over its own contact bank or by operating said irst switch to connect with said second switch.

1.2. In a telephone or like system, a plurality of ,first switches, 'a second switch accessible to all of said first switches, 'a rplurality of subscribers linesv each connected in' multiple to the contact banks of all of said switche's,"means for operating any one'of said rst switches to connect lover its contact bankv with Vany one of said lines or with said second switchy and, 'if said secondV 

